###########################################################################
# Concurrent server - webserver3f.py                                      #
#                                                                         #
# Tested with Python 2.7.9 & Python 3.4 on Ubuntu 14.04 & Mac OS X        #
###########################################################################
import errno
import os
import signal
import socket
 
SERVER_ADDRESS = (HOST, PORT) = '', 8999
REQUEST_QUEUE_SIZE = 1024
 
def grim_reaper(signum, frame):
    pid, status = os.wait()
 
def handle_request(client_connection):
    request = client_connection.recv(1024)
    print(request.decode())
    http_response = b"""
HTTP/1.1 200 OK
 
Hello, World!
"""
    client_connection.sendall(http_response)
 
def serve_forever():
    listen_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    listen_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    listen_socket.bind(SERVER_ADDRESS)
    listen_socket.listen(REQUEST_QUEUE_SIZE)
    print('Serving HTTP on port {port} ...'.format(port=PORT))
 
    signal.signal(signal.SIGCHLD, grim_reaper)
 
    while True:
        try:
            client_connection, client_address = listen_socket.accept()
        except IOError as e:
            code, msg = e.args
            # restart 'accept' if it was interrupted
            if code == errno.EINTR:
                continue
            else:
                raise
 
        pid = os.fork()
        if pid == 0:  # child
            listen_socket.close()  # close child copy
            handle_request(client_connection)
            client_connection.close()
            os._exit(0)
        else:  # parent
            client_connection.close()  # close parent copy and loop over
 
if __name__ == '__main__':
    serve_forever()